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Research Letters in Materials Science
Volume 2009, Article ID 657284, 4 pages
Research Letter

Cyclic Deformation Behavior and Fatigue Crack Propagation of Low Carbon Steel Prestrained in Tension

1Department of Material Science and Engineering, Saitama Institute of Technology, Fusaiji 1690, Fukaya, Saitama 369-0293, Japan
2Department of Material Science and Engineering, University of Science and Technology Liaoning, Anshan, Liaoning 114051, China

Received 30 March 2009; Accepted 20 May 2009

Academic Editor: Daolun Chen

Copyright © 2009 J. G. Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The tests were performed on low carbon steel plate. In the tension fatigue tests, two angle values (𝜙=0 and 𝜙=45, 𝜙 is the angle between the loading and the rolling direction) have been chosen. The influence of strain path change on the subsequent initial work softening rate and the saturation stress has been investigated. Dislocation microstructure was observed by transmission electron microscopy. It was found that the strain amount of preloading in tension has obviously affected the cyclic softening phenomenon and the initial cyclic softening rate. It was observed that the reloading axial stress for 𝜙=45 case increased more than that of 𝜙=0 case, due to the anisotropism of Q235. In the fatigue crack propagation tests, the experimental results show that with increasing the pretension deformation degree, the fatigue crack growth rate increases, especially at the near threshold section.